In various analyses such as chemical examination, environmental analyses and biotechnological research, a diaphragm pump and a valve device which are equipped with a diaphragm are employed in order to feed an accurate quantity of a fluid being treated.
For example, Patent document 1 discloses a diaphragm pump having a structure such that a diaphragm is secured between a pair of frames, wherein the frames are mutually-coupled by the use of pairs of screws and screw nuts in order to suppress a leakage of the fluid from an edge portion of the diaphragm.